AS IF David Cameron hadn't had a bad enough week already, Boris Johnson popped up on the Today programme this morning to further increase the pressure on the beleaguered Prime Minister, calling the government's stance on London airport capacity "a policy of utter inertia".

The London mayor took to the airwaves ahead of today's launch by Sir Howard Davies of his air capacity report, commissioned by the PM in an effort to kick the issue into the long grass until after the next election.

Johnson favours the building of a brand new Thames Estuary airport – the sooner the better - and opposes vehemently the politically-charged idea of increasing capacity at Heathrow.

This morning Johnson pooh-poohed ideas to either build a third runway at Heathrow or increase the efficiency of the airport through 'mixed-mode' flying, allowing simultaneous use of runways for take-offs and landings.

"In order to get mixed mode at Heathrow, which would be violently unpopular, it would take at least 10 years," the mayor told Today. "On the current timetable it would take until 2020 to get permissions and that's very optimistic. The runway at Heathrow simply will not happen."

Johnson said there was "absolutely no need" to delay making a decision about building a new airport. "In the next 10 years they will build 52 new runways in China. In the UK they will build nil. It is a policy of utter inertia."

The mayor's renewed attack comes hot on the heels of Michael Heseltine's government-commissioned growth report, which this week claimed that unless the question of new runways being built around London is resolved within a year the economy will suffer.

Following on from the government's defeat in the Commons on Wednesday on an amendment demanding a cut in contributions to the EU by an unholy alliance of Tory rebels and Labour MPs, this is rapidly becoming another week to forget for the Tory high command.

Labour leader Ed Miliband's taunts on Wednesday at PMQs that Cameron was increasingly coming to resemble his Conservative predecessor John Major are being supported on a daily basis, with splits over Europe and turmoil in the party reinforcing the public perception of an administration in perpetual chaos.

As Martin Ivens noted recently in The Sunday Times, the Downing Street press operation, shorn of a "thug" in the mould of Alastair Campbell or Andy Coulson, needs to change the way it works and become more street-smart in dealing with the media.

"I don't advise him to adopt new Labour's cynical spin-doctoring — it disguised a lack of substance in Blair's first years of government and its moral inadequacy eventually became a bad news story in itself," Ivens wrote. "But he needs help and advice from outside his charmed circle if he is to win."

A perfect example of the party's lack of grip occurred yesterday, when the Evening Standard gave its front page to the accusation by a former Home Office mandarin that Cameron has surrounded himself with a narrow, male-dominated "Old Etonian clique" that is difficult for women politicians to "penetrate".

That the Standard, a rightward-leaning newspaper whose editor Sarah Sands is well-connected with the Tory party, saw fit to splash with Dame Helen Ghosh's claims illustrates Cameron's problem. Even supportive newspapers now feel that 'Tory chaos' stories are fair game.